The U.S. ambassador to Libya has died after being attacked by militiamen storming the U.S. consulate in the eastern city of Benghazi, reports say, according to BBC News.

The ambassador was said to be among four U.S. officials killed in a protest over a U.S.-produced film that is said to insult the Prophet Muhammad.

The U.S. state department has only confirmed the death of one official - but it has not named him.

Protesters over the film have also attacked the U.S. embassy in Cairo.